Percussive tool for scaling boiler surfaces



v P. e. HANDOLL PERCUSSIVE TOOL FOR SCALING BOILER SURFACES Filed March 30, 1921' w T k a %W v w% V M II. M w fi m Mm) fih /A/////////////////////////// QN ANA l v v l IU V/// //////./////.//MW//////// //////////////V/ \IL\ N b b .Q

Patented F ch. 23, 1926.

1,574,l9ii

To all whom it may concern.

Be it known that PERCY GILBERT nonmof 68 Wisteria Road, Lewisham, Lon don, England, has invented certain new and 5 useful Improvements in Percussive Tools for Scaling Boiler Surfaces, of which the PERCY GILBERT HANDOLL, or LEWISI-IAM, LONDON, ENGLAND.

PERCUSSIVE TOOL FOR SCALING BOILER SURFACES.

Application filed March 30, 1921. Serial No. 457,129.

following is a specification.

This invention relates-topercussive tools for sealing boiler tubes or other surfaces, and has for its object to provide a pneumitic or fluid pressure tool which shall be simple in construction and reliable in opera- My improved tool comprises two main parts or members, viz. an inner member which serves as a guideand is held iirmly with its front end against the tube, plate, or other surface during the operation of the tool, and an outer member or percussive body mounted toreciprocate longitudinally upon the inner member and formed tion.

with cutting edges on its forward end.

An annular chamber or space is formed between the inner member and the percussive body mounted thereon to which the pressure fluid is admitted continuously and operates to reciprocate the percussive body as hereinafter described.

The percussive body is cylindrical in shape and its ends which have circular openings and lit around parts of the inner me1nber of different diameters, constitute the ends of the pressure chamber and are so dimensioned that the forward end prese iits a larger area to the action of the pressure fluid than the rearend. this difference the tendency of the pressure fluid is to force the percussive body forward, and means are provided whereby the pressure on the forward end of the percus= sive body is relieved when that body ap proaches the limit ofrits forward stroke,- allowing the pressure exerted on the rear end to effect the return stroke. For this purpose exhaust apertures or outlets are run covered by the percussive body near the end of the forward stroke, and the front and rear portions of the annular pressure chamher or space are separated more or less or communication between them is cut oif momentarily by an enlargement or collar on the inner member moving into a part of the chambered interior of the percussive body which fits more or less closely around the c llar,

HAN-

In consequence of In the accompanying sheet of illustrative drawings 2- a Figxl is a longitudinal section of a scalin toolconstructed according to this ins vention. V

Fig

2 aside elevation of the same and 8 and at are transverse sections on the llnes 3 3 and l-4 respectively of Fig. 1. a

As shown, a percussive body a of cylindrical shape and formed with a serrated cutting end face a is supported and guided upon the inner member Z) the forward end 3) of which is adapted to beheld against. the work whilst the other endis fitted with a hollow T piece coupled by a sleeve 0* with a tubular handle (Z which is coupled in turn with a-iiexible tube forthe supply of compressed air or other pressure fluid.

The inner member I) is bored or otherwise formed with an axial inlet a for the pressure fluid extending from its rear end and terminating in a radial passage or passages f located at some distancefrom the rear end behind an annular shoulder or enlargement Between the percussive body or cylinder (4- and the inner member 7), is formed an enclosed annular space or chamber 7 which in all positions of the percussive body a remains in communication with the pressure fluid inlet c through the radial passage or passages f referred to.

Atrits front end is an enlarged annular-chamber or spacey. 'llhe'percussive body a is free to reciprocate on theinner member I) under the action of thefpressure fluid, the range of movement in either direction being limited by the annular externally grooved shoulder or enlargement b on the inner member which lit-s the chamber 7 but is smaller than the chamher The enlargement b separates or cuts communication between thefront and rear annular spaces giand g as the outer member descends and the enlargement b enters the space g.

The front chamber 5/ is open to the exhaust it along the part Z) when the outer member is in its lower posi 01 working s roke isofgr a er area than the rear end a? of the same which is constantly subjected to pressure. The rear end becomes effective to actuate the percus sive body only at the end of the forward stroke when the fluid pressure operating on the larger end a is exhausted through outlets at that end provided by formingflav tened portions h or: grooves on the reducedend of the inner member orin other ways.

In order to permit of the mounting of the percussive body or cylinder over the inner member the rear end a is formed of aremovable ring which is screwed into position and secured by a locking pin held in position by a wire'ring a The inlet end of the bore a in the inner member I) is internal ly screwthreaded to-receive'the T piece 0 for the connectionof the handle and pressure fluid supply tube.

A valve 2' is provided in the hollow T piece 0 for admitting and shutting off the pressure fluid and the valve spindle is fitted with a detachable mushroom head 71 arranged to serve the dual purpose of controlling the valve andapplying pressure to the tool. hen pressure is applied to the head 2" by the hand of the operator the valve is opened a ainst the action of a spring j which tends pressure fluid is admitted through the inlet passages e, f to the chamber g. The passage g being closed by being entirely below the enlarged vportion b of the inner member, the fluid acts only against the rear end a of the chamber and forces the percussive member a back into the position shown in full lines in Figs. 1 and 2. v

- In this position the enlarged or ported part 9 of the cylinder a is put in free communication with the inlet passages admitting the pressure fluid to the front end of the chamber 9 where operating on the larger member adapted to be held firmly against the work, an outer member forming the percussive body mounted to reciprocate longitudinally on the inner member and forming with the inner member an annular pressure chamber or space, against the opposite ends of which the pressure fluids acts to effect the forward and return strokes of the percussive body, and meanscontrolling the supply, distributionand exhaust of the pressure fluid substantially as described.

2. An improved percussive scaling tool operated byfluid pressure and comprising an inner stationary member having passages for the pressure fluid,-an outer reciprocatory percussive body guided on the inner member and co-operating therewith to distribute the pressure fluid, and having cutting edges on the forward end thereof a hollow handle with pressure fluid supply connection coupled with the rear end of the inner memberand a valve in the supply connection fitted with a head adapted to serve for open- .ing the valve and applying hand pressure to the tool. V

3. An improved percussive tool including an inner member bored axially and radially with pressure fluid passages, an outer reciprocating member constituting the percussive body and forming a pressure chamber around the inner member receiving pressure fluid through said passages, the relative dimensions of the ends of the pressure Chilll'l' ber being such that thetforward end presents a larger area to the action of the pressure fluid than the rear end, means on the inner member for separating the front and rear portions of the pressure chamber and opening the forward end to the atmosphere when the percussive body approaches the end of the forward stroke substantially as and for the purpose described.

In testimony whereof he atfixes his signa ture.

PERCY GILBERT HANDOLL. 

